The specific objective of this research project is to evaluate the factors which contribute to the regulation of the heart peripheral circulation. This involves evaluating the relative contribution of neural reflexes from the arterial baroreceptor, cardiopulmonary receptors and autoregulation. Animal models include conscious dogs and anesthetized cats. Studies include the identification of neural pathways regulating the cardiovascular response to acute myocardial ischemia and the interaction of reflexes arising from the cardiopulmonary and arterial baroreceptors.